[time-nuts] So what’s inside that Cs Beam Tube anyway?

jimlux jimlux at earthlink.net
Mon Oct 31 19:41:27 EDT 2016

On 10/31/16 3:28 PM, Richard (Rick) Karlquist wrote:
> The ghost of Jack Kusters is now spinning in his grave on
> this Halloween night.  Jack was a fairly opinionated
> guy and it didn't take much to get him excited.
> Jack used to rail against people who asked this naive
> question.  There are any number of reasons why this
> doesn't make sense.  One major one is that everything
> in the tube is thoroughly "cesiated" as Jack put it.
> Another is:  how do you determine which parts to replace?
> Another is:  is this economically feasible?

This is a classic question on small volume manufacturing (which I'm sure 
these tubes are)..

The only "rebuildable" (vacuum) tubes I've seen are things like very 
high power transmitting tubes, high voltage rectifiers, and high power 
ignitrons or mercury arc rectifiers.   All in the "hundreds of kV" or 
"hundreds of kW" kind of range.  I think they can rebuild smaller 
transmitting tubes (10-20 kW), too.

I've seen a  1930s-40s era Cockroft Walton generator with not just 
rebuildable rectifiers, but it's not even sealed: you run the 
(diffusion) vacuum pump when you're operating it.   The other things are 
not exactly a tube, but things like pelletrons, dynamitrons, and 
febetrons also tend to have a vacuum pump associated with them.

In this case, there are "user serviceable" parts inside - either because 
they're mechanical devices, or because there's a fairly high probability 
of internal localized and repairable damage from a flashover.

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